Contact sleeves are, as a rule, hollow metallic cylinders. They serve e.g. as sockets for banana plugs. It is, however, also possible to arrange a number of contact sleeves alongside one another, so that a plug with a corresponding number of plug contacts can be inserted.
Contact sleeves are usually, as illustrated in FIG. 1, placed in a bore 3 piercing a circuit board 1. The contact sleeves are connected with the circuit board 1 at their two ends by a solder connection 5, 7. A cylindrical inner surface of the bore 3 and annular disk-shaped regions bordering the ends of the bore are provided with metallizing 9. The solder connections 5, 7 create a mechanical securement of the contact sleeve 11 and an electrical connection between the contact sleeve 11 and the metallizing 9 of the circuit board 1. The metallizing 9 is electrically connected through at least one conductor path 13 on the circuit board.
Usually the circuit boards are manually provided with the contact sleeves and the solder connections are either also formed manually or else in a wave solder bath.
Modern electrical instruments, especially measurement instruments, contain, as a rule, at least one circuit board, on which the electronic components are arranged. These components must be secured mechanically on the circuit board and connected electrically to conductors running in or on the circuit board. To reduce the manufacturing costs, surface-mountable components, so-called “surface mounted devices”, or, for short, SMD components, are preferably used. SMD components do not require holes in the circuit board for their mounting. Instead, they are soldered directly with their contacts onto connections provided for them.
Typically, in a first step, a solder paste is applied in a screen printing process onto the circuit board at all places where components are to be subsequently positioned. A place where solder is applied or where, after the end of the manufacturing process, a solder connection exists, is called a solder location in the following.
In a next step, the circuit boards are populated with the components by machine. The populated circuit boards are then brought into an oven, especially a reflow oven. The soldering process takes place in an oven, e.g. in a protective gas atmosphere, where a solder-specific temperature cycle is carried out.
Today, most electronic components are available as SMD-components, and this has led to a considerable reduction in the manufacturing costs of electronic instruments. Unfortunately, there are still some components that cannot be mounted and connected together with SMD-components in one procedure. The manual populating and connecting of these components results in a high, additional expense.